This invention relates generally to refrigerant compressor units and, in particular, to a refrigerant compressor in which oil is separated from the compressed refrigerant gas.
A conventional refrigerant compressor unit comprises a compressor housing, a cylinder block mounted therein having a plurality of cylinders, and a plurality of pistons respectively slidably and closely fitted within the cylinders. The pistons are driven within the cylinders to compress refrigerant gas. The compressor housing includes a chamber adjacent the cylinder block containing piston driving elements, and a cylinder head having a suction chamber and a discharge chamber which operatively communicate with the cylinders.
A charge of refrigerant gas and lubricating oil is introduced into the compressor unit. In the operation of the compressor, the refrigerant gas is compressed by the pistons reciprocating within corresponding cylinders. The compressed refrigerant gas circulates from the discharge chamber through the cooling system and returns to the compressor unit at the suction chamber. The lubricant oil passes into the crank chamber together with the refrigerant gas as blow-by through the gap between the piston and the inner wall of its corresponding cylinder to lubricate therebetween. The lubricant oil is separated from the refrigerant gas in the crank chamber and lubricates the moving parts therein.
In order to return the blow-by gas into the suction chamber, the conventional compressor unit is provided with a passageway or a balance hole which communicates between the crank chamber and the suction chamber. Accordingly, the lubricant oil returns to the suction chamber to lubricate the pistons and cylinders.
However, the oil mixed with the refrigerant gas passes through the outlet port and circulates in the cooling system and contaminates the inner wall of the conduits in that system. This means not only that lubricant oil is wasted unreasonably, but also that the efficiency of heat exchange in the system is lowered.